THE AC LINE FITTING OVERHEATED CAUSING IT TO EXPLODE AND ARC WHICH IN TURN MELTED THE PRIMARY WIRING HARNESS FOR THE ENGINE. THIS ALSO RESULTED IN THE WIRE CATCHING FIRE AND CAUSING BURN DAMAGE TO THE FIREWALL. THE VEHICLE WAS GOING THROUGH A CAR WASH WHEN THE INCIDENT OCCURRED. I HAVE BEEN TOLD BY MY MECHANIC THAT THE WATER FROM THE CAR WASH PREVENTED FURTHER FIRE DAMAGE.